/*
 * Copyright (c) 1998, Michael Smith
 * Copyright (c) 1996, Sujal M. Patel
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>

/*
 * Machine-independant ISA PnP enumerator implementing a subset of the
 * ISA PnP specification.
 */
#include <stand.h>
#include <string.h>
#include <bootstrap.h>
#include <isapnp.h>

#define	inb(x)		(archsw.arch_isainb((x)))
#define	outb(x, y)	(archsw.arch_isaoutb((x), (y)))

static void	isapnp_write(int d, int r);
static void	isapnp_send_Initiation_LFSR(void);
static int	isapnp_get_serial(uint8_t *p);
static int	isapnp_isolation_protocol(void);
static void	isapnp_enumerate(void);

/* PnP read data port */
int		isapnp_readport = 0;

#define	_PNP_ID_LEN	9

struct pnphandler isapnphandler =
{
	"ISA bus",
	isapnp_enumerate
};

static void
isapnp_write(int d, int r)
{
	outb(_PNP_ADDRESS, d);
	outb(_PNP_WRITE_DATA, r);
}

/*
 * Send Initiation LFSR as described in "Plug and Play ISA Specification",
 * Intel May 94.
 */
static void
isapnp_send_Initiation_LFSR(void)
{
	int cur, i;

	/* Reset the LSFR */
	outb(_PNP_ADDRESS, 0);
	outb(_PNP_ADDRESS, 0); /* yes, we do need it twice! */

	cur = 0x6a;
	outb(_PNP_ADDRESS, cur);

	for (i = 1; i < 32; i++) {
		cur = (cur >> 1) | (((cur ^ (cur >> 1)) << 7) & 0xff);
		outb(_PNP_ADDRESS, cur);
	}
}

/*
 * Get the device's serial number.  Returns 1 if the serial is valid.
 */
static int
isapnp_get_serial(uint8_t *data)
{
	int	i, bit, valid = 0, sum = 0x6a;

	bzero(data, _PNP_ID_LEN);
	outb(_PNP_ADDRESS, SERIAL_ISOLATION);
	for (i = 0; i < 72; i++) {
		bit = inb(isapnp_readport) == 0x55;
		delay(250);	/* Delay 250 usec */

		/* Can't Short Circuit the next evaluation, so 'and' is last */
		bit = (inb(isapnp_readport) == 0xaa) && bit;
		delay(250);	/* Delay 250 usec */

		valid = valid || bit;

		if (i < 64) {
			sum = (sum >> 1) |
			    (((sum ^ (sum >> 1) ^ bit) << 7) & 0xff);
		}

		data[i / 8] = (data[i / 8] >> 1) | (bit ? 0x80 : 0);
	}

	valid = valid && (data[8] == sum);

	return (valid);
}

/*
 * Fills the buffer with resource info from the device.
 * Returns nonzero if the device fails to report
 */
static int
isapnp_get_resource_info(uint8_t *buffer, int len)
{
	int		i, j;
	uchar_t	temp;

	for (i = 0; i < len; i++) {
		outb(_PNP_ADDRESS, STATUS);
		for (j = 0; j < 100; j++) {
			if ((inb(isapnp_readport)) & 0x1)
				break;
			delay(1);
		}
		if (j == 100) {
			printf("PnP device failed to report resource data\n");
			return (1);
		}
		outb(_PNP_ADDRESS, RESOURCE_DATA);
		temp = inb(isapnp_readport);
		if (buffer != NULL)
			buffer[i] = temp;
	}
	return (0);
}

/*
 * Scan Resource Data for useful information.
 *
 * We scan the resource data for compatible device IDs and
 * identifier strings; we only take the first identifier string
 * and assume it's for the card as a whole.
 *
 * Returns 0 if the scan completed OK, nonzero on error.
 */
static int
isapnp_scan_resdata(struct pnpinfo *pi)
{
	uchar_t	tag, resinfo[8];
	uint_t	limit;
	size_t	large_len;
	uchar_t	*str;

	limit = 1000;
	while ((limit-- > 0) && !isapnp_get_resource_info(&tag, 1)) {
		if (PNP_RES_TYPE(tag) == 0) {
			/* Small resource */
			switch (PNP_SRES_NUM(tag)) {
			case COMP_DEVICE_ID:
				/* Got a compatible device id resource */
				if (isapnp_get_resource_info(resinfo,
				    PNP_SRES_LEN(tag)))
					return (1);
				pnp_addident(pi, pnp_eisaformat(resinfo));
				return (0);

			case END_TAG:
				return (0);

			default:
				/* Skip this resource */
				if (isapnp_get_resource_info(NULL,
				    PNP_SRES_LEN(tag)))
					return (1);
				break;
			}
		} else {
			/* Large resource */
			if (isapnp_get_resource_info(resinfo, 2))
				return (1);

			large_len = resinfo[1];
			large_len = (large_len << 8) + resinfo[0];

			switch (PNP_LRES_NUM(tag)) {
			case ID_STRING_ANSI:
				str = malloc(large_len + 1);
				if (isapnp_get_resource_info(str,
				    (ssize_t)large_len)) {
					free(str);
					return (1);
				}
				str[large_len] = 0;
				if (pi->pi_desc == NULL) {
					pi->pi_desc = (char *)str;
				} else {
					free(str);
				}
				break;

			default:
				/* Large resource, skip it */
				if (isapnp_get_resource_info(NULL,
				    (ssize_t)large_len))
					return (1);
			}
		}
	}
	return (1);
}

/*
 * Run the isolation protocol. Upon exiting, all cards are aware that
 * they should use isapnp_readport as the READ_DATA port.
 */
static int
isapnp_isolation_protocol(void)
{
	int		csn;
	struct pnpinfo	*pi;
	uint8_t		cardid[_PNP_ID_LEN];
	int		ndevs;

	isapnp_send_Initiation_LFSR();
	ndevs = 0;

	isapnp_write(CONFIG_CONTROL, 0x04);	/* Reset CSN for All Cards */

	for (csn = 1; ; csn++) {
		/* Wake up cards without a CSN (ie. all of them) */
		isapnp_write(WAKE, 0);
		isapnp_write(SET_RD_DATA, (isapnp_readport >> 2));
		outb(_PNP_ADDRESS, SERIAL_ISOLATION);
		delay(1000);	/* Delay 1 msec */

		if (isapnp_get_serial(cardid)) {
			isapnp_write(SET_CSN, csn);
			pi = pnp_allocinfo();
			ndevs++;
			pnp_addident(pi, pnp_eisaformat(cardid));
			/*
			 * scan the card obtaining all the identifiers it holds
			 */
			if (isapnp_scan_resdata(pi)) {
				/* error getting data, ignore */
				pnp_freeinfo(pi);
			} else {
				pnp_addinfo(pi);
			}
		} else {
			break;
		}
	}
	/* Move all cards to wait-for-key state */
	while (--csn > 0) {
		isapnp_send_Initiation_LFSR();
		isapnp_write(WAKE, csn);
		isapnp_write(CONFIG_CONTROL, 0x02);
		delay(1000); /* XXX is it really necessary ? */
		csn--;
	}
	return (ndevs);
}

/*
 * Locate ISA-PnP devices and populate the supplied list.
 */
static void
isapnp_enumerate(void)
{
	int		pnp_rd_port;

	/* Check for I/O port access */
	if ((archsw.arch_isainb == NULL) || (archsw.arch_isaoutb == NULL))
		return;

	/*
	 * Validate a possibly-suggested read port value. If the autoscan failed
	 * last time, this will return us to autoscan mode again.
	 */
	if ((isapnp_readport > 0) &&
	    (((isapnp_readport < 0x203) ||
	    (isapnp_readport > 0x3ff) ||
	    (isapnp_readport & 0x3) != 0x3))) {
		/* invalid, go look for ourselves */
		isapnp_readport = 0;
	}

	if (isapnp_readport < 0) {
		/* someone is telling us there is no ISA in the system */
		return;
	} else if (isapnp_readport > 0) {
		/*
		 * Someone has told us where the port is/should be,
		 * or we found one last time.
		 */
		isapnp_isolation_protocol();
	} else {
		/* No clues, look for it ourselves */
		for (pnp_rd_port = 0x80; pnp_rd_port < 0xff;
		    pnp_rd_port += 0x10) {
			/* Look for something, quit when we find it */
			isapnp_readport = (pnp_rd_port << 2) | 0x3;
			if (isapnp_isolation_protocol() > 0)
				break;
		}
	}
}
